The UNC Macromolecular Interactions Facility, also called "Mac-In-Fac" (web address: macinfac.bio.unc.edu), is a core facility of the University of North Carolina at Chapel Hill. The facility has been operating since 1996. The facility has a Biacore X, a Biacore 2000, a Beckman Optima XL-A analytical ultracentrifuge with scanning UV/VIS optics, a fluorescence spectrophotometer, differential scanning and isothermal titration calorimeters, circular dichroism spectropolarimeters, and static and dynamic light scattering instruments. There are no similar facilities on the UNC Chapel Hill Campus, or nearby institutions. Its current users come from 11 departments on the UNC Chapel Hill campus (Biochemistry & Biophysics, Biology, Cell Biology, Chemistry, Microbiology & Immunology, Pathology, Pediatrics, Pharmacology, Pharmacy, Physics, and Physiology), other academic and research institutions from North Carolina and several Research Triangle Park biotechnology companies. Many of our users have experienced problems while carrying out their projects using the absorbance optics available with the Optima XL-A analytical ultracentrifuge. These and other projects need to be carried out with the interference optics available with the Optima XL-I. Additionally, some other users have a need for an analytical ultracentrifuge with a fluorescence optics-based detection system (please see attached specific research plans). No such instrumentation is available in this geographical area (Chapel Hili-Raleigh-Durham- RTP). Therefore, the Mac-ln-Fac requests funds for: (1) purchasing an interference and absorbance optics based analytical ultracentrifuge (Beckman Optima XL-I), and (2) purchasing and installing a fluorescence optical detection system in our existing Optima XL-A (this accessory will be manufatured and installed by The Center to Advance Molecular Interaction Sciences (CAMIS), University of New Hampshire). [unreadable] [unreadable]